The present invention relates generally to a numerical machine tool, and more particularly to a hydraulic-pneumatic loop control device for binding and locating an added head of the numerical machine tool.
The upright numerical machine tool is commonly used in the industry. In operation, the tool is directly fitted under the process main shaft head of the machine body to work on a workpiece in an upright manner. In the event that the workpiece must be processed sideways, at a specific angle, or by extending the main shaft nose, the numerical machine tool must be provided with an added head to facilitate the operating of the numerical machine tool. The conventional way for mounting an added head on the numerical machine tool is generally done by the fastening bolts. As shown in FIGS. 1 and 2, a main shaft 1 is provided in the underside with a plurality of threaded holes 2. An added head 3 is provided in the top with a plurality of bolt holes 4 corresponding in location to the threaded holes 2 of the main shaft 1. In the process of mounting the added head 3, a tool retainer 6 in the main shaft 1 is used to retain a tool sleeve 7 of the top of the added head 3 such that the added head 3 is suspended. Thereafter, the added head 3 is fastened with the main shaft 1 by a plurality of fastening bolts 5 which are engaged with the threaded holes 2 of the main shaft 1 via the bolt holes 4 of the added head 3. Such a conventional fastening method as described above is rather inefficient and time-consuming at best. In addition, the threaded holes 2 of the main shaft 1 and the bolt holes 4 of the added head 3 must be made with precision at additional cost. Furthermore, the added head 3 must be repeatedly adjusted and fastened so as to facilitate the operating of the added head 3 at various angles. It is therefore readily apparent that the conventional way of fastening the added head 3 with the main shaft 1 is not cost-effective.
It is therefore the primary objective of the present invention to provide a hydraulic-pneumatic loop control device for fastening an added head with the main shaft of a numerical machine tool. The device comprises two cylinder mounts and a piston located between the two cylinder mounts. The piston is provided with a hydraulic trough and a pneumatic through, which are in communication with a hydraulic-pneumatic loop. The piston is linked at the lower end with an engagement block. The piston is driven to displace by the hydraulic-pneumatic loop so as to control the engagement and the disengagement of the engagement block with a retaining block of the added head. In the process of mounting the added head, the added head is first place on the machine stand before the piston is driven by the hydraulic-pneumatic loop so as to actuate the engagement block to move downwards, thereby causing the engagement block to move away from the urging portion of the lower cylinder. In the meantime, the main shaft makes use of a numerical servocontrol to move downward such that a tool retainer catches the top of a tool sleeve of the added head, and that the retaining block of the added head is located at a standby position. As the piston is driven by the hydraulic-pneumatic loop to cause the engagement block to rise such that the engagement block is pressed by the urging portion of the lower cylinder, and that the engagement block is engaged with the retaining block of the added head. The device of the present invention is efficient and devoid of the fastening bolts of the prior art.
It is another objective of the present invention to provided a device for fastening an added head with the main shaft of a numerical machine tool. The main shaft and the added head are provided with a crank-tooth coupler to facilitate the adjusting of the processing angle of the added head with ease and speed.
It is still another objective of the present invention to provide a device for fastening an added head with the main shaft of a numerical machine tool. The device is provided with. a spring which is disposed between the piston and the lower cylinder mount for preventing the engagement block from being actuated by the piston to rise at such time when the power outage takes place in the midst of the operation of the numerical machine tool. Such incident can result in the disengagement of the added head with the main shaft of the numerical machine tool.
It is still another objective of the present invention to provided a device for fastening and locating an added head with the main shaft of a numerical machine tool. The device is provided with a protective cover having a retaining portion by means of which the protective cover is retained by the engagement block of the piston.
The foregoing objectives, features, functions, and advantages of the present invention will be more readily understood upon a thoughtful deliberation of the following detailed description of a preferred embodiment of the present invention with reference to the accompanying drawings.